Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25–29, 2009: Oral Presentations
Background and Objective:
Seasonal variation is consistent with an environmental aetiology. The aim of this study was to investigate seasonal variation in cancer incidence in children and young people, using population-based data.
Data on all cases diagnosed during the period 1968-2005 were extracted from The Northern Region Young Person's Malignant Disease Registry. The following diagnostic groups were analysed: leukaemia, lymphoma, central nervous system tumours, sympathetic nervous system tumours, retinoblastoma, renal tumours, hepatoblastoma, bone tumours, soft tissue sarcoma, germ cell tumours and carcinomas. The chi-squared heterogeneity test was used to test for departure from uniform distribution. Poisson regression analysis was used to fit sinusoidal (harmonic) models to the data, using month of birth and month of diagnosis, respectively, as covariates in separate models. The sinusoidal model assumption was assessed using the chi-square goodness of fit test. Analyses were carried out separately by gender and age group (0-14, 15-24 years).
There were a total of 5909 childhood cancer cases; 2959 aged 0-14 years (1659 males, 1300 females) and 2950 aged 15-24 years (1590 males, 1358 females). For 0-14 year old boys, there was statistically significant seasonal variation in month of birth for acute non lymphocytic leukaemia (P = 0.04; peak in September) and astrocytoma (P = 0.03; peak in October). Based on month of diagnosis, there was statistically significant seasonal variation in girls for lymphomas (P = 0.05; peak in March) and Hodgkin lymphoma (P < 0.01; peak in January), and in boys for osteosarcoma (P = 0.05; peak in October). For 15-24 year olds, significant seasonal variation in month of birth for malignant melanoma in females (P = 0.03; peak in March) and cervical carcinoma (P = 0.03; peak in October) was observed.
These findings suggest that seasonal environmental factors, particularly around the time of birth, such as infections or exposure to sunlight may be involved in the aetiology of specific diagnostic groups.